Many large circulation periodicals are gathered on a binding line for stitching, trimming, bundling, and shipping. The binding line typically may include a plurality of signature feeding apparatus, commonly called packer boxes, each of which may have a driven rotary drum with a plurality of signature grippers disposed about the periphery thereof, and the signature grippers may be adapted to grip signatures seriatim as they are received from a signature supply means after they have been shifted therefrom to the rotary drum by cam driven suction means or other like components. Conventionally, the suction means will include oscillating suction grippers together with a vacuum control valve operatively associated therewith.
In the case of saddle stitched books, a packer box will open the pages of a signature so that it may be dropped onto a saddle conveyor or gathering chain. The gathering chain then conveys that signature on a particular chain space to the next packer box which may, in like manner, drop still another signature in straddle relation on top of the previously so distributed signature or signatures. In this manner, a book comprised of an entire collection of different signatures can be gathered on the saddle conveyor or gathering chain for stitching.
As will be appreciated by those skilled in the art, a book is simply a collection of signatures, each of which may have a backbone, a head, a foot, and a pair of folios, regardless of the number of signatures and regardless of the manner in which the book is bound.
In more recent years, the books that are gathered on a binding line have been customized and/or personalized by utilizing a variety of different techniques. Typically, this has involved computer control systems whereby different combinations of packer boxes along a binding line are selectively disabled and enabled in order to thereby customize books in accordance with demographics or the like. As a result, there has been a need to be able to monitor operation of the various packer boxes on a binding line in a manner that is entirely satisfactory.
Even when the books that are gathered on a binding line are not customized and/or personalized, monitoring of the packer boxes is important. It is sometimes the case that a packer box will malfunction and, thus, not successfully feed a signature onto a chain space of a gathering chain, and, in addition, it sometimes happens that the wrong signatures will be supplied to a particular packer box. If either of these occur, a correct signature that is needed for a given book will not be delivered to the gathering chain as required.
As a result, the book that was being formed will be defective and must be discarded and reordered. It is, of course, possible by means of calipers to determine when a signature has failed to be delivered, but, if the wrong signatures have been improperly loaded into a given packer box, detection is rendered far more difficult, meaning that it is highly likely that significant waste will occur because of the time interval before detection is likely to be noted. As a result, it has remained to eliminate this known problem area in the operation of binding lines.
The present invention is directed to overcoming one or more of the foregoing problems and achieving one or more of the resulting objectives.